This application claims the benefit of priority to Japanese Patent Application 2001-243027 filed Aug. 9, 2001.
1. Technical Field of the Invention
The present invention relates to a liquid crystal device which displays images, for example, characters, numeric characters, and graphics, by modulating light with a liquid crystal. Furthermore, the present invention relates to electronic apparatus comprising the liquid crystal device.
2. Description of the Related Art
In recent years, liquid crystal devices have been used widely as display portions of various sorts of electronic apparatuses, such as cellular phones, portable data terminals, etc. In these liquid crystal devices, generally, a pair of substrates individually provided with electrodes are attached to each other such that electrode-side surfaces face each other while a constant interval, that is, a so-called cell gap, is kept and, in addition, a liquid crystal is encapsulated in the cell gap.
As this liquid crystal device, a liquid crystal device of an active matrix system, in which a liquid crystal is driven by a switching element, and a liquid crystal device of a simple matrix system, in which a liquid crystal is driven without the use of the switching element, have been known. Examples of liquid crystal devices of active matrix systems include those using three-terminal type active elements, such as a TFT (Thin Film Transistor), etc., and those using two-terminal type active elements, such as a TFD (Thin Film Diode), etc, as the switching elements.
As a conventional liquid crystal device, for example, one having a structure shown in FIG. 10 has been known. This liquid crystal device 51 includes a pair of substrates 53a and 53b attached to each other by a sealing material 52, and as shown in FIG. 11, a liquid crystal is encapsulated in the space formed between these substrates, that is, in a cell gap, and therefore, a liquid crystal layer L is formed. The cell gap is maintained to have a constant dimension by spacers 67 dispersed on the surface of any one of the first substrate 53a and the second substrate 53b. 
In FIG. 10, on the surface of the first substrate 53a on the liquid crystal L side, a plurality of linear line wirings 56 are arranged in parallel with each other and, therefore, arranged in the shape of stripes while pixel electrodes 54 are formed on individual line wirings 56 with TFD elements 57 therebetween. Since the line wirings 56 are formed in the shape of stripes, the pixel electrodes 54 are arranged in the shape of a dot matrix. As shown in FIG. 11, an orientation film 58a is formed on the surface of the first substrate 53a, on which the pixel electrodes 54 are formed.
In FIG. 10, in order to clearly show the structures of the pixel electrode 54 and the TFD element 57, those elements are schematically shown to be enlarged, and the interval between those adjacent to each other is schematically shown to be larger than in practice.
The first substrate 53a includes a substrate overhang portion 59a overextending beyond a perimeter of the second substrate 53b, and an IC 61a for driving the liquid crystal is mounted on the surface of the substrate overhang portion 59a by an ACF (Anisotropic Conductive Film) 65. That is, a COG (Chip On Glass) mounting system is performed. Each of the line wirings 56 extends outside the sealing material 52, and the tip thereof is connected to a terminal, that is, a bump (not shown in the drawing), of the IC 61a for driving the liquid crystal.
On the surface of the second substrate 53b on the liquid crystal L side, a plurality of linear electrodes 62 are arranged in parallel with each other and, therefore, arranged in the shape of stripes. These electrodes 62 are formed nearly perpendicularly to the line wirings 56 on the first substrate 53a and, furthermore, are formed with the positional relationship of facing individual pixel electrodes 54.
The second substrate 53b includes a substrate overhang portion 59b extending beyond the perimeter of the first substrate 53a, and an IC 61b for driving the liquid crystal is mounted on the surface of the substrate overhang portion 59b by an ACF 65. That is, mounting a COG (Chip On Glass) mounting system is performed. Each of the electrodes 62 extends outside the sealing material 52, and the tip thereof is connected to a terminal, that is, a bump (not shown in the drawing), of the IC 61b for driving liquid crystal.
As shown in FIG. 11, a transflective film 63 is formed on the surface of the second substrate 53b on the liquid crystal L side, a color filter film 64 is further formed thereon, and an overcoat layer 66 is further formed thereon. The aforementioned electrodes 62 are formed on the overcoat layer 66, and an orientation film 58b is formed on those electrodes 62.
A phase difference plate 68a is installed on the outer surface of the first substrate 53a, and a polarizing plate 69a is further installed thereon. A phase difference plate 68b is installed on the outer surface of the second substrate 53b, and a polarizing plate 69b is further installed thereon. An illumination device 71 which acts as a backlight is installed at the position facing the outer surface of the second substrate 53b on which the polarizing plate 69b is installed.
In FIG. 10, a point at which the pixel electrode 54 and a counter electrode 62 overlap one another constitutes one dot, and one color picture element, for example, one color picture element of R, G, or B, of the color filter film 64 shown in FIG. 11 is installed corresponding to this one dot. Three color dots of R, G, and B constitute one unit and, therefore, one pixel is formed.
In FIG. 10, one of the ICs 61a and 61b for driving the liquid crystal supplies scanning signals to corresponding pixel electrodes 54 or corresponding counter electrodes 62, the other of those ICs 61a and 61b for driving the liquid crystal supplies data signals to corresponding pixel electrodes 54 or corresponding counter electrodes 62 and, thereby, the orientation of the liquid crystal in a plurality of pixels arranged in the shape of a dot matrix is controlled.
In FIG. 11, when the surroundings of the liquid crystal device 51 are bright, external light incident from the first substrate 53a side is reflected at the transflective film 63 and is supplied to the liquid crystal layer L. When the surroundings of the liquid crystal device 51 are dark, the illumination device 71 emits light, and the light passes through the transflective film 63 and is supplied to the liquid crystal layer L. The light thus supplied to the liquid crystal layer L is modulated on a pixel basis by the liquid crystal, the orientation thereof being controlled on a pixel basis. According to this, an image is displayed outside the first substrate 53a. 
In FIG. 10, the region partitioned by a plurality of pixel electrodes 54 arranged in the shape of a matrix is a drive region, that is, an effective display region V, and images, such as characters, numeric characters, etc., are formed in this effective display region V. A dummy pixel region W1 is formed outside the effective display region V while succeeding thereto, and a metal film region W2 is further formed outside the dummy pixel region W1 while succeeding thereto.
In the dummy pixel region W1, as a matter of form, a pattern in the same shape as the pixel electrodes 54 is formed. However, the pattern formed here is not a transparent electrode material, such as ITO (Indium Tin Oxide), but the portions corresponding to the electrodes are covered with opaque metal films. According to this, this dummy pixel region W1 is made to be a light-shielding region.
The metal film region W2 is formed from, for example, a metal constituting the TFD element 57, e.g., Ta (tantalum), and is also made to be a light-shielding region. As described above, the light-shielding regions W1 and W2 are formed between the effective display region V and the sealing material 52. These light-shielding regions W1 and W2 increase the contrast of the effective display region V by darkening the surrounding of the effective display region V, that is, by reducing the light transmittance and, therefore, improve display quality.
However, regarding the conventional liquid crystal device 51 shown in FIG. 10, since the substrate overhang portion 59a, on which the IC 61a for driving liquid crystal is mounted, and the substrate overhang portion 59b, on which the IC 61b for driving liquid crystal is mounted, overhang in directions different from each other, the external shape of the liquid crystal device 51 becomes horizontally asymmetric with respect to the effective display region V and, therefore, there has been a problem in that handling of the liquid crystal device 51 has become inconvenient.
In order to overcome this, the applicant of the present invention suggests a structure in which, as shown in FIG. 12, the substrate overhang portion 59 is installed on only a first substrate 53a, and both of the IC 61a for driving the liquid crystal on the first substrate 53a side and the IC 61b for driving the liquid crystal on the second substrate 53b side are mounted in common on the substrate overhang portion 59. In this liquid crystal device 81, since both of the ICs 61a and 61b for driving liquid crystal are mounted on one substrate overhang portion 59, the external shape of the liquid crystal device 81 becomes horizontally symmetric with respect to the effective display region V and, therefore, handling becomes very easy.
In this liquid crystal device 81, conducting materials 72 are dispersed and mixed in the inside of the sealing material 52. Subsequently, wirings 73, one end of which is connected to a terminal, that is, a bump (not shown in the drawing), of the IC 61b for driving the liquid crystal on the second substrate 53b side and the other end of which goes into the inside of the sealing material 52 and contacts the conducting material 72, are formed on the liquid crystal side surface of the first substrate 53a concurrently with the line wirings 56. On the other hand, the tips of the counter electrodes 62 formed on the second substrate 53b are extended into the inside of the sealing material 52 and contact the conducting material 72. As described above, the wirings 73 on the first substrate 53a side and the counter electrodes 62 on the second substrate 53b side are electrically conducted and connected with each other through the conducting material 72.
In the liquid crystal device 81 having the structure shown in FIG. 12, it is also desired that a light-shielding region is installed around the effective display region V and, display quality is improved. Regarding the conventional liquid crystal device 51 shown in FIG. 10, in order to install the light-shielding region around the effective display region V, the dummy pixel region W1 and the metal film region W2 are formed around the effective display region V on the surface of the first substrate 53a, on which TFD elements 54 are formed. In consideration of this, regarding the liquid crystal device 81 shown in FIG. 12 as well, it seems possible to install a light-shielding region around the effective display region V and to improve display quality if the dummy pixel region W1 and the metal film region W2 are formed around the effective display region V on the first substrate 53a. 
However, regarding the liquid crystal device 81 having the structure shown in FIG. 12, since the wirings 73 are formed between the effective display region V and the sealing material 52 on the surface of the first substrate 53a, on which the TFD elements 57 and the pixel electrodes 54 are formed, the dummy pixel region W1 and the metal film region W2 cannot be formed in this region and, therefore, another problem occurs in that the light-shielding region can not be formed in this region.
The present invention was made in consideration of the aforementioned problems. Accordingly, it is an object of the present invention to provide a structure, in which a light-shielding region can be formed around an effective display region without any trouble, regarding a liquid crystal device having a structure in which a conducting material and a wiring are formed.